Ever trying to cut and paste a URL into Firefox but the URL is spawned into multiline so that you need to delete the line break yourself? Andrei Zmievski has posted a tips on how to make Firefox smarter to remove the line break:
Here’s another Mozilla/Firefox tip: if you copy a URL wrapped over multiple lines from somewhere and try to paste it into the address bar, you will end up only with the first line of it. To fix it, go to about:config and change editor.singleLine.pasteNewlines setting to 3 or add:
to your user.js file. Now all the line breaks will be removed upon pasting.